Aerial photography

ABSTRACT

Discrete lengths of elongated web are both pushed and pulled through a complex path formed in part by spaced-apart guides made of porous material. Pressurized gas forced into the path through the porous walls creates gas layers over which the webs ride. Means are also provided for transporting the webs between stationary and moving paths.

United States Patent Scott 1 Dec. 26, 1972 [54] AERIAL PHOTOGRAPHY3,125,268 3/1964 l3a1'tholomay...; ..226/97 Inventor: Richard DavidScott Camden, NJ. 3,468,606 9/1969 Wolf et al. ..226/97 UX 73 AssigneezC Corporation FOREIGN PATENTS OR APPLICATIONS [22] Filed: March 19, 19711,904,101 1/1969 Germany "226/97 [21] Appl' 126,112 PrimaryExaminer-Allen N. Knowles Attorney-H. Christoffersen [52] US. Cl..226/97, 226/197 51 1111.0. ..B65h 17/32 1 1 AB TRA [58] Field ofSearch ..226/97, 7, 95,197,196; Discrete lengths of elongated web areboth pushed 242/76 and pulled through'a complex path formed in part byspaced-apartguides made of porous material. Pres- [56] keferfmces Cit-edsurized gas forced into the path through the porous UNITED STATESPATENTS walls creates gas layers over which the web's ride. 1 Means arealso provlded for transportmg the webs 3,245,334 4/1966 Long ..226/97 Xbetween stationary and moving paths. 3,548,783 12/1970 Knapp ...226/l973,134,527 5/1964 Willis ..226/97 7 Claims, 7 Drawing Figures PNENIED HEB26 m2 SHEET 1 U? a INVENTOR. char D. Scott ATTORNEY PATENTED DEC 25 1972SHEET 2 0F 4 Fig 4.

ATTORNEY PATENTEU DEC 2 6 1972 SHEET 3 OF 4 I N VEN TOR. Richard D.Scott /QM ATTORNEY PATENTEU DEC 26 I972 SHEET 4 [IF 4 INVENTOR. RichardD. Scott fiaw nd X '1 AERIAL PHOTOGRAPHY The invention herein describedwas made in the course of a contract with the U-.S. Government.

BACKGROUND O THE DISCLOSURE Y There is a need in many art areas forapparatus for which is moving relative to the first. In the prior artmuch apparatus exists for permitting a web to be pulled through complexpaths. However, where the web is of finite length, apparatus must becapable of both pushing and pulling it. The apparatus described in thepresent invention allows the web to be both pulled and pushed throughmany complex paths.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a mechanical schematic of anaerial panoramic camera which employs the present invention to guidediscrete lengths of an elongated film web;

- FIG. 2 is a view, partially in section, showing a capstan assemblyused to drive a web' in the apparatus of FIG. 1;

FIG. 3 is a perspective view of a curved web guide employed to guide theweb through the apparatus of FIG. 1; 1

FIG. 4 is a mechanical schematic of a web transfer mechanism; i

FIG. 5a is a perspective view of a rotating camera mechanism employingthe present invention;

FIG. 5b is a broken-away view of the rotating camera of FIG. 5a toillustrate the web guides contained within the revolving camera; and vFIG. 50 is a perspective showing of the stationary mechanism in whichthe camera of FIG. 5a is positioned.

SUMMARY OF THE INVENTION According to a feature of the invention, thewalls of the web guiding passages may comprise elongated porous elementsformed as parallel, developable surfaces. Gas may. be forced through thewalls into the passages for creating gas layers between the web surfacesand the walls.

DETAILED DESCRIPTION Referring first to FIG. 1, which illustratesschematically an aerial panoramic camera, elongated webs of photographicfilm are stacked one on top of the other in a supply magazine 12. Thesewebs may be 4 X constantly'to slowlyrotate by a motor coupled to 48inches, as one example. A pick-up device 14 which, for example, may beasuction mechanism, removes the webs one at a time from the stack andmoves each one into a capstan assembly 16. A webis moved via a series ofother capstans (not shown) at appropriate places in the mechanism intorotating camera assembly 18 through opening 21. The camera assembly iscaused the camera.

aperture plate 31 and lens assembly 32. The aperture plate may have anaperture 29 one-half inch high by the width ofthe film. A mirror 33 at a45 angle relative to the plane of the page on which the drawing isreproduced permits an object, such as a section of terrain 34, to berecorded on the flattened portion 36 of the filmas the aircraft (notshown) transporting the camera proceeds in the direction of arrow 35.Webs 10 pass through the camera in serial fashion being propelled atappropriate points by capstans within the camera (which are not shown inFIG. 1) and emerge from the camera through opening 22. The webs are thenguided to a web capture mechanism 24. The'webs 10 are guided-betweenfirst and second rolls of continuous webbing 26 and 28 respectively andonto a driven take-up roll 30. The film later may be removed fromtake-up roll 30 for processing.

Since rather complex transfer mechanisms are needed to pass the filmbetween the fixed assemblies 12 and 24 and rotating assembly 18, it mayseem logical to merely include all mechanisms within rotating camera 18.However, in'the type of camera contemplated, the weight of the filmalone-may be of the order of 500 pounds and may equal the weight ofcamera 18 as it presently exists. Since the angular velocity of camerarotation must continuously'b'ear a fixed relationship to the speed ofthe aircraft over the ground, as the aircraft changes speed, so mustwthecamera. Increasing the weight of assembly 18, increases substantiallythe torque requirement and therefore weight of motor 20. In anyairborne-equipment such as the contemplated camera, weight is always aproblem.

In FIG. 1, no web guides are shown and only one typical capstan 16 isshown. Adescription of the actual web guides, the capstans and themechanism for per mitting entry of webs 10 into revolving camera 18 willbe given shortly in connection with other figures. Also, film webs 10must be contained within a light tight container at all times (exceptwhen passing aperture plate 31) to avoid exposing the film.

Referring to FIG. 2, which shows, in cross section, a

capstan assembly suitable for use in the camera mechanism of FIG. 1, aweb 10 (shown in phantom) is wrapped around capstan 50 in an arc ofapproximately The capstan is coupled to and driven by a servo, 7

capstan assembly. The inner walls of each of the plenums, that is, thewalls next to the web 10, are made of a porous material such as"sintered bronze. These walls are numbered respectively 64, 66 and 68.The compressed gas exits through the porous walls 68 thereby forcing webinto contact with the surface of capstan 5,0. The purpose of fingers S6is to guide the web ll) out of the capstan assembly. For example, ifcapstan 50 is driven in the direction of arrow 70, air coming throughwall 64 would tend to cause the web to wrap around the drum'in thevicinity of portion 72 of the drum. However, fingers 56 cause the web tobe guided between inner and outer flanges 52 and 54 and to exit from thecapstan assembly.

It will be noted that the capstan assembly has finger projections 56 onboth the ingress and egress-sides of the assembly. While the fingers arenot needed on the ingress side, the symmetrical arrangement shownpermits the use of a single design ofcapstan assembly with the servomotormerely being wired for clockwise or counterclockwise motion ofcapstan 50. Alternatively,

left and right capstan assemblies might have to be provided to allow theassemblies to be placed wherever they are needed in the camera of FIG.1.

Capstan assemblies are positioned in FIG. 1 at a distance apart lessthan the length of an individual film web. For example, if a web havinga'length of four feet is used, capstan assemblies must be positioned adistance apart no greater than approximately 3 feet, nine inches. Thiswill ensure that a web is at all times being pushed or pulled by atleast one capstan assembly.- i

Referring next to FIG. 3, there is shown a curved web guide assemblysuitable for use in guiding the web through curved regions 80 in FIG. 1.The curved web guide comprises first and second web guides 90 and 92,one on each side of the web 10 shownin phantom. The first and second webguides are spaced apart by spacers such as 94 a distance just sufficientto permit passage of web 10 therebetween. At opposite ends of the curvedweb guides are flanges 96, 97 which permit fastening the curved webguide to other web guiding members, such as, for example, the capstan ofFIG. 2. Each of web guides 90 and 92 includes a plenum 100. A compressedgas, such as pressurized air from source 102, is forced into the plenums100 via the orifice in tubing 104 connecting the compressed gas sourcewith the plenums. I 1

The inner wall of each of web guides 90 and 92 (that is, the wall nextto web 10) is made of a porous material such as sintered bronze. A gasunder pressure in plenums 100 is thereby caused to escape through porouswalls 106 and 108 and thereby lubricate the surfaces between which web10 travels.

Each of the porous walls 106 and 108 is formed as a d evelopablesurface. That means that the wall is formed without stretching,shrinking or kinking the metal in any way. This may be accomplished bywrapping a rectangular piece of the sintered bronze in helical fashionaround a cylindrical mandral a fraction of a turn. Walls formed in thismanner permit a web to be either pushed or pulled through thecurvedguide without any tendency to move to either side. Spacers 94 are justthat. They do not act to guide the web through the guide. (In practice,due tothe additional spacing between walls in excess of web thickness, a

very slight side thrust develops which may be corrected by lateral webguides placedin the guides to which a curved guide is attached.) It willbe noted that the guide shown in FIG. 3 causesthe direction of the webto change through 90", while moving it from a first plane in thevicinity of flanges 96 to a second parallel but noncoincident plane inthe vicinity of flanges 97.

By ending the curved portion'short of that shown in FIG. 3 or extendingit for a further distance, the web can be guided through a turn of moreor less than 90. The curved guide may be connected as mentionedpreviously to a capstan of the type shown in FIG. 2, to

another curved guide or to sections of straight guide as will be broughtout more fully in connection with the description of FIG. 5. i

The mechanical schematic of FIG. 4 will be used to illustrate theapparatusused to move a web from a first mechanical assembly to a:second mechanical assembly moving relative to the first. Let it beassumed that assembly 110 which comprises everything to the left of andabove web 10 (shown in phantom) is stationary. Further, let itbe assumedthat assembly 112 which .comprises everything to the right of web 10 isrevolving in the direction of arrow 114. The only exception is thatsupport 116, having axis 117 about which assembly 112 rotates, is fixedrelative to assembly 110. Then assumes that it is desired to move web 10from fixed assembly 1 10 to rotating assembly 1 12.

Both the fixed and rotating'assemblies 110 and 112 include a capstanassembly 16a and 161), respectively,

of the type illustrated in FIG. 2. The leading edge of i the dashed line122. The grooves cooperate with finger-like projections 124 on wall-126which forms a portion of capstan drive assembly 16b. These fingerlikeprojections are similar to those shown in FIG. 2 and numbered 56. Wall128 on moving assembly 1 12 is similar to wall except that it has nogrooves in its inner surface.

In operation, rotating assembly 112 is caused to rotate constantly inthe direction of 1 14 by a motor, not shown. The leading edge of web 10is introduced into capstan 16a of the fixed assembly 110, the capstanbeing caused to rotate in the direction of arrow 130. By proper timing,the web is propelled from capstan 16a into the space between the twowalls just as capstan 16b of moving assembly 112 is positioned oppositethe capstan 16a. The surface speed of web 10, determined by capstanassembly 16a, must be greater than the surface speed of wall 128relative to wall 120. Then web 10 will be driven into the space definedby walls 120 and 128. As the web enters the space between walls 120 and128 the capstan assembly 16b may have reached a point beyondcapstan-assembly (that is, lower than cap- "mai no grooves 122 of wall120 ensure that the web will be driven into capstan assembly 16b.Capstan assembly 16b is driven in the direction of arrow 132 at asurface speed which is the difference between the I surface speed ofcapstan assembly 16a and the surface speed of wall 128 relative to wall120. The moving web exits into the interior portion of revolvingassembly 112 in the vicinity of opening 134 where it may be utilized forany purpose desired; 7

The length of walls 120 and 128 are determined by the length of web tobe transferred and to the speed with which the web moves relative torotating assembly 122. The longer the web or the faster the speed ofassembly 112, the longer must be walls 120 and 128. Because the twowalls 120 and 128.form arcs of cylinders about pivot axis 117 thespacing between the two walls remains constant as the one assembly movesrelative to the other. While assembly 110 was described as beingstationary and 112 was described as being fixed, these are relativeterms. Also, while the walls 120 and 128 are shown as arcs of cylinders,they may in fact be flat such that wall 128 is caused to move linearlywith respect to wall 120.

A mechanism similar to that illustrated in FIG. 4 may also be used totransfer webs from a moving to a fixed assembly with thefollowingmodifications; The rotation direction of the capstan in capstanassemblies 16a and 16b are reversed from direction arrows 130 and 132.Wall 128, not wall 120, contains grooves. The cooperating finger-likeprojections are part of capstan assembly 16a, not 16b. Then, if thesurface speed of the capstan of capstan assembly 16b exceeds therelative surface speed between walls 120 and 128, the web will be driveninto the space defined by the walls and into capstan assembly 16a. 7

FIG. 5a shows an-actual rotating camera assembly 18 such as was depictedschematically in FIG. 1, which is rotated by a motor 20 via hollow shaft140. A sleeve 141 permits compressed air from a source-(not shown) to bepassed through shaft 140 to camera 18 to provide lubrication in thevarious web guides to be described.

Wall 128 corresponds to the similarly numbered wall in FIG. 4. Thecapstan assembly 16b corresponds .to the similarly numbered capstan inFIG. 4 and is of the type illustrated and described in FIG. 2. A web(not shown) is guided between the exposed surface of wall 128 andanother wall 120 fixed in space and illustrated in FIG. SC, to bedescribed shortly. After the web is driven through capstan assembly 16b,it enters the camera body through opening 21. The web then traverse theinterior of the camera assembly, in a manner to be described inconnection with FIG. 5b, and existsat opening 22 shown at the back side(as illustrated) of the camera assembly. It then lies between and isguided by walls 162 and 164 to capstan assembly 16c. Capstan assembly160 and grooved wall 166 form part of a transfer mechanism similar tothat shown in FIG. 4. Here the inner moving wall 166 is grooved.

I FIG. 5b shows the camera with the exterior walls cut away to permitviewing the various web guide assemblies within the camera. The web 10,shown in phantom view, enters the camera body at opening 21. It then isguided through a curved web guide 170 of the type illustrated in FIG. 3.It will be noted that no pressurized gas lines are shown. This is toavoid increasing the complexity of FIG. 5b. However, the gas lines arepresent as shown in FIGS. 2 and 3 wherever needed. The web next passesbetween spaced web guides 172 and 174 which may be constructedwithporous inner walls and It will be noted that the web guides aresubstantially I separated in the vicinity of region 176. This allows forslack in the web between capstan assembly 16b (FIG. 5a) and capstanassembly 16d, for the purpose of improving servo control, and avoidingscuffing of the web.

In FIG. 50 rotating camera assembly 18, shown in phantom, is inserted inposition in the fixed assembly 200. For the sake of simplicity, supplymagazine 12 and capture mechanism 24, shown schematically in FIG. 1,have been eliminated from FIG. 5c. Assembly 200 contemplates beingsupplied from two supply magazines 12, each feeding into Y assembly 202.This may be useful where films of two different types maybe used (e.g.color and black and white). A web emerging from the base of Y assembly202 is driven by capstan 16a into the space between wall 120, shown inFIG. 5c and 128, shown in FIG. 5a. The numbers 16a, and 128 correspondwith similar components shown in FIG. 4. After a web emerges fromrevolving camera assembly 18,- it passes between wall 204 and groovedwall 166, FIG. 5a. A capstan assembly 16e contains finger-likeprojections, not visible, which cooperate with the grooves in wall 166,FIG. 5a. A web traversing the space between walls 204 and 166 is engagedby capstan assembly 16e and driven thereby through curved webguideassembly 206 to capture mechanism 24 (FIG. 1).

Having described the arrangement of the various components of thecamera, its operation will now be described with reference as needed toFIGS. 1, 5a, 5b and 5c. An elongated web 10 is pushed from a supplymagazine 12 through Y assembly 202 (FIG. 5c) and into capstan assembly16a. During this time, camera assembly 18 is slowly continuouslyrotating. The timing of the entry of the leading edge of web 10 intocapstan assembly 16a coincides with the position of capstan assembly 16bopposite capstan assembly 16a. Therefore, the web emerges betweengrooved wall 120 and wall 128 connected to the rotating camera assembly18. Since the web 10 has a surface speed greater than the surface speedof wall 128 relative to wall 120, it will be driven into capstanassembly 16b. Finger projections 124 (FIG. 5a) on capstan assembly 1611cooperating with the grooves in wall 120 ensure that the web willcaptured by capstan assembly 16b. The web is transferred between 16a and16b as the camera 18 rotates and as the capstan 16b is moving away fromcapstan 16a. As the web emerges from capstan assembly 16b, itpasses intothe body of the rotating camera assembly through opening 21.

The web next proceeds through a curved web guide between walls 172 and176 and into the camera re- .7 gion 180, as best seen am. 512. Thepath-length within the camera is such that as the leading edge of theweb reaches a position opposite the aperture in aperture plate 31,mirror 33 attached to camera .18 is in 7 rotation are such that eachrevolution of the camera results in the recording on the film of apicture of anarrow band of terrain extending from oneedge to the otherof the long dimension of the film. Accordingly, after n camerarevolutions, n film strips have been recorded each strip of a differentnarrow sector of the terrain the aircraft has passed over (there may besome overlap). These strips, after'being developed, then may be placededge-to-ed ge (the 48' edges abutting or slightly overlapping oneanother) to build up a two dimensional map of the terrain passed over bythe aircraft. I

The actual-path taken by the film after exposure most easily may be seenin FIG. b. The exposed film .enters capstan assembly 16d and is driventhereby through curved web guide assembly184 to exit from the-camera 18at opening 22. The web then traverses the space between the walls 162and 164, FIG. 5a, and is engaged by capstan assembly 16c. The length ofweb 10, the travel distance within camera assembly 18 and the speed withwhich camera assembly 18 rotates are all interrelated in such a mannerthat as the web reaches caps tan assembly 160, that capstan assembly isjust opposite capstan assembly 16a. As camera assembly 18 continues torotate, the web emerging-from capstan assembly 16c will be containedbetween walls 166 and 204 as it is engaged and driven by capstanassembly l6e toward the capture mechanism 24.

While the description has been given in terms of a single elongated web10, it will be seen from FlG. 1 that a series of webs one behind theother are continuously driven through the rotating camera assembly.While the invention has been described in the context of an aerialpanoramic camera, it will be understood by those familiar with the artthat the invention may be used in connection with any elongated strip ofweb material which it is desired to be pushed and/or pulled along acircuitous and complex path. 4

What is claimed is:

1. Means for transporting a web from a supply mechanism to a receivingmechanism moving relative to the supply mechanism comprising, incombination:

two parallel guide members, one attached to eachof said supply andreceiving mechanisms, saidtwo members forming between them a web guiding2. The combination as set forth in claim 1 wherein said guide membersare curved and are moved relative to one another about a common. axis ofrotation, said means for propelling said web into and. removing said 4web from the space between said guide members being coupled to directsaid web in a direction normal to said axis of rotation.

3. The combination as set forth in claim 2 wherein said coupled meansare capstan drive means.

. 4. The combination as set forth in claim 1 wherein said guide memberscomprise porous material and further including means for supplying a gasto said porous material at a pressure elevated from that'of theenvironment in which said transporting means is placed.

5. in combination: v a stationary first guide member formed as an arc ofa first circular cylinder; a movable second guide member formed as anarc of a second circular cylinder concentric withthe first and movableabout their common axis, said two members forming between them aparallel-walled web guiding passage; means for propelling a web intosaid passage in the direction of movement of said second guide member;and 3 a means coupled to said second guide member for engaging said weband propelling it out of said passage.

6. The combination as set forth in claim 5 further including means formoving said movable guide members at a speed, X, relative to saidstationary guide member;

and wherein said means propelling said web into said passage includesmeans for propelling said web into said passage with a speed,. Y,relative to said stationary guide member and said means propelling saidweb out of said passage includes means for propelling said web with aspeed, Z, relative to said movable guide member, where Z Y X.

7. The combination as set forth in claim 5 further including means formoving said movable guide member at a speed, X, relative to saidstationary guide member;

and wherein said means propelling said web into said passage includesmeans for propelling said web into said passage with a speed, Y,relative to said movable guide member and said means propelling said webout of said passage includes means for propelling it with a speed, Z,relative to said stationary guide member, where Z Y- X.

1. Means for transporting a web from a supply mechanism to a receivingmechanism moving relative to the supply mechanism comprising, incombination: two parallel guide members, one attached to each of saidsupply and receiving mechanisms, said two members forming between them aweb guiding passage; means for propelling a web into said passage in thedirection of movement of said receiving mechanism; and means coupled tosaid receiving mechanism for engaging said web in said passage andpropelling it out of said passage into said receiving mechanism.
 2. Thecombination as set forth in claim 1 wherein said guide members arecurved and are moved relative to one another about a common axis ofrotation, said means for propelling said web into and removing said webfrom the space between said guide members being coupled to direct saidweb in a direction normal to said axis of rotation.
 3. The combinationas set forth in claim 2 wherein said coupled means are capstan drivemeans.
 4. The combination as set forth in claim 1 wherein said guidemembers comprise porous material and further including means forsupplying a gas to said porous material at a pressure elevated from thatof the environment in which said transporting means is placed.
 5. Incombination: a stationary first guide member formed as an arc of a firstcircular cylinder; a movable second guide member formed as an arc of asecond circular cylinder concentric with the first and movable abouttheir common axis, said two members forming between them aparallel-walled web guiding passage; means for propelling a web intosaid passage in the direction of movement of said second guide member;and means coupled to said second guide member for engaging said web andpropelling it out of said passage.
 6. The combination as set forth inclaim 5 further including means for moving said movable guide members ata speed, X, relative to said stationary guide member; and wherein saidmeans propelling said web into said passage includes means forpropelling said web into said passage with a speed, Y, relative to saidstationary guide member and said means propelling said web out of saidpassage includes means for propelling said web with a speed, Z, relativeto said movable guide member, where Z Y - X.
 7. The combination as setforth in claim 5 further including means for moving said movable guidemember at a speed, X, relative to said stationary guide member; andwherein said means propelling said web into said passage includes meansfor propelling said web into said passage with a speed, Y, relative tosaid movable guide member and said means propelling said web out of saidpassage includes means for propelling it with a speed, Z, relative tosaid stationary guide member, where Z Y - X.